Telephone-exchange system.



OSVALD 1:..Msmussnn, or'wns'r nonoxnn', NEW JERSEY, ASSIGNOZR. To wnsrnzm .ELECTRIC COMPANY, .mconrona'rnnor NEW YQRK, n. Y., A CORPORATION or NEW -YORK.

To all whom itmay concern." Y

Be it known that I, GsVALD E. RASMUS- mm, a subject of the King. of Denmark residing at West Hoboken, in the county of Hudson and State of New Jersey, have invented certain new and useful Improve- -ments in Telephone Exchange Systems, of

which the following is a full, clear, concise, and exact description.

This invention relates to improvements in electrical switching ,systems, and more particularly to improvements in automatic numerical switches used in automatic and mechanism.

semi-automatic telephone exchange systems.

The object of this invention is to provide more reliable controlling devices in a power driven revertive impulse control switch Heretofore, certain switches of this type have employed, for reasons connected with their mechanical construction, four brushes to travel over abank of terminals arranged in sets of three, in which case two of the four brushes engaged one terminal. These two brushes were then electrically connected and acted as a single brush. In this invention, however, they are not so connected, but instead, are connected through a suitable circuit to two windings of a relay. This relay counts off the terminals or groups of terminals as the brushes pass-over them, and actuates an escapement wheel from aset to a normal position.

The drawing represents diagrammatically a telephone system employing the present invention. Only so much of the system is shown as is necessary to a clear understanding of the same.

In the accompanying drawing, this invention is illustrated in an embodiment of a final selector or connector switch adapted for tens and units selection, but it will readily be understood that the invention may apply to switches adapted for other purposes, and to switches of different construction.

A clear understanding may be had from the following detailed description.

S represents a calling substation; S a called substation; and CS a connector switch through which a connection between these wo substations may be established.

It will be assumed that the usual connec tions have been established. through wellknown line finders and first selectors, and that the lines from substation .8 have been Specification of Letters Patent:

I 4 Patented Jan. 1, 1918. Application nieu November 17, 1916. Serial No. 181,859.

connected through to the terminals of the side-switch arms 1 and 2 of the connector sw'itchCSL, A' circuit is thereupon est'ab: l shed from grounded battery, left -'hand winding of relay LR, contact and side tac't, right-hand winding of relay LE to ground. The armature of relay LR is attracted and establishes a circuit from grounded battery, winding of relay 3, alter-- nate contact and armature of relay LR to ground. Relay 3 is energized and attracts its armature, thereby completing an energizing circuit for-the escape magnet 9. This circuit may be traced from ground, armature and normal contact of relay LR, armature and alternate contact'of relay 3, first osition contact and wiper 8 of the side switch, winding of escapement magnet 9 to grounded battery. Escapement magnet 9 is slow to release and will not deenergize during short periods of time-in which current does not flow through it.

Subscriber S now sends out, by means of his dial switch D, impulses for the selection of the tens group of contacts. The armature of relay LR is caused to vibrate in unison with these impulses, but the circuit through slow-release relay 3 is. broken off for such a short space of time that it, like magnet 9 does not release its armature. Therefore, periodic impulses are sent through the following circuit: from ground, armature and normal contact of relay LR, armature and alternate contact of relay 3, side-switch arm 4 in its first position, stepping magnet 5 to grounded battery.

Stepping magnet 5 is impelled to actuate its armature to step ratchet wheel 6 the'pre-v scribed number of steps, corresponding to the impulses sent out from the, dial switch D.

The. stepping of ratchet wheel 6 is accomtherewith and normally resting in the notch I 30, pushes the ratchet wheel 12 away from,

wheel 6 andslides over the surface of the former. The outward thrust given to the ratchet wheel 12'is communicated through collar 13 to a member 15 to actuate contact springs 16, 17 and-18. The normal contacts of these springs are broken and connection with their'alternate contacts established.

A circuit is thereupon established from ground, contact spring 18 and its alternate contact, magnet 19 to grounded battery. The resulting movement of the armature of magnet 19 releases a clutch arrangement 20 so that a spindle 21 of a brush carriage 22 normally held stationary thereby, is released in a downward direction under the force of gravity. The carriage 22 supports four brushes, of which 23 and 24 are representative, arranged to travel over and make contact with the rows of fixed termmals 25, 26 and 27, which are grouped in the wellknown manner as indicated on the drawing.

- As the brushes 23 and 24 come in contact with the middle terminal 26 of the set of terminals 25, 26 and 27, a circuit is established from grounded battery, the righthand winding-of relay 28, alternate contact and spring 17, brush 24, terminal 26, brush 23, spring 16 and its alternate contact, lefthand winding of relay 28 to ground.

I Relay 28 responds to this energization by attracting its armature. A latch 29, mounted on the armature of relay 28, allows the ratchet wheel 12 to escape one step upon each forward movement of the armature of relay 28. It should be noted at this point, that relay 28 may be so designed that its armature will not be retracted when the contacts 23 and 24 leave one contact 26 and pass to the next contact 26. However, when the contacts 23 and 24 pass from the last contact 26 in a group to the first contact 26 in the next group, this space being .very much greater than that between contacts within a group, the armature of relay 28 is allowed to make a full backward movement. Ratchet Wheel 12 will therefore be stepped once for'each group of terminals 25, 26 and 27, passed by the brush carriage 22, and as soon as it has taken as many steps as its associated ratchet wheel 6, the member 14 will resume its original position in the notch 30 in ratchet wheel 12 and thereby allow contact springs 16, 17 and 18 to return to normal. Circuit for the clutch magnet 19 is broken at spring 18, and the brush carriage 22 is stopped just beyond the counted group through the engagement of spindle 21 by the clutch 20.

All of this action takes place in such a short space of time that its completion is practically synchronous with the end of the train of impulses sent out by the dial switch 1).

As the subscriber at substation S is preparing to make the units selection, the en- .energize relay 42 is set up itaeaoae suing time interval between the last impulse of the tens selection and the first impulse of the units selection .is long enough to allow slow-release relay 9 to retract its armature. The retraction of its armature sets the sideswitch wipers into the second position.

The impulses for the units selection actuate relay LR in a manner similar to that previously described. This time, however, through the movement of side-switch wiper 4, stepping magnet 33 is actuated to step a ratchet wheel 34 similar in construction to ratchet Wheel '6. The outward thrust given thereby to a ratchet wheel 35, in a manner similar to that described in connection with ratchet wheels 6 and 12, operates contact springs 36, 37 and 38. A circuit is now es tablished from ground, spring 18 and its normal contact, spring 38 and its contact 39, magnet 40, to grounded battery. The energization of magnet 40 presses the spindle 21 against a constantly rotating roller 41 in the well-known manner to drive brush carriage 22 in an upward direction. When brushes 23 and 24 engage the first terminals in the group which has been selected, a circuit to from grounded battery, right-hand winding of relay 42, contact and spring 37, normal contact and spring 17 brush 24, terminals 26, brush 23, spring 16 and its normal contact, spring 36 and its contact, left-hand winding of relay 42 to ground. It should be noted at this point that. relay .42 is designed to respond to the separate contacts over ,which it passes, so that these contacts are counted off on .the ratchet wheel 35, until the proper terminal has been reached, at which time ratchet and wiper 8 of the side switch, slow-release relay 9, to grounded battery. When the operation of the impulse counting device represented by ratchet wheels 34 and 35 has been completed, this circuit is broken at contact 43 and the escapement magnet in its deenergization steps the side-switch wipers into their third position.

It should be noted that the operation of relays 28 and 42 is not aifected by the potentials found on terminals 26, since the energization of one winding of either of these relays is suiiicient for its operation.

When the side-switch wipers move into their third position, a circuit is completed from ground, relay 00 individual to the line, the terminal 26 upon which the brushes 23 and 24 are located, brush 24, contact and wiper 32 of the side switch release ma operate the release magnet 44.

The movement of side switch wipers 1 and 2 into their third position connects together the substations S and S The subscriber S is summoned in the usual manner and upon the conclusion of the con-- versation the connector switches are caused to resume their normal position. When the calling party replaces his receiver on its switchhook, a ground is placed onconductor 45 in a Well-known manner over the first selector and line finder, and a circuit is established from this ground, conductor 45, side-switch wiper 31 and its associated third position contact, contact and side-switch wiper 32, winding of release magnet 44 to grounded battery. A circuit is thereupon established from ground, right-hand armature and contact of relay 44, winding of up;

drive magnet 40 to grounded battery. Through this circuit the up-drive magnet 40 is energized in response to which the brush carriage 22 is returned to its normal position. Upon the energization of relay 44 a holding circuit is established from ground, off-normal contact 46, left-hand armature and contact of relay 44, the winding of relay 44 to grounded battery, and this circuit is maintained until the brush carriage 22 has' resumed its normal position and the off-normal contact 46 has been opened thereby.

It is not intended that the invention be limited to the specific disclosure made here-' in, but shall only be limited by the appended 40- claims.

What is claimed is: 1. In an electrical switching system, sets of fixed terminals, movable brushes arranged to travel over and make contact with said terminals, means for moving said brushes, and a circuit including an electromechanism and .two of said brushes, said circuit being closed through one of said terminals in each set to control the movement of said brushes.

2. In an electrical switching system, an impulse transmitter, sets of fixed terminals,

movable brushes arranged to travel over ing an electromechanism and two of said brushes, said circuit being closed through one of said terminals in each set, a ratchet member controlled by said impulse transmitter, and an escape member associated with said ratchet member and controlled by said electro-mechanism to control the movement of said brushes.

4. In an electrical switching system, an impulse transmitter, sets of fixed terminals, movable brushes arranged to travel over and make contact with said terminals, a circuit including an electromechanism and two of said brushes, said circuit being .closed through one of said terminals in each set, a ratchet member controlled by said impulse transmitter, an escape member associated with said ratchet member andcontrolled by said electromechanism, means to drive said brushes, and a circuit contzy olling'device associated with said ratchet member and said escape member to control said driving means.

' In witness whereof I hereunto subscribe my name this 16th day of November, A. D., 1916.

OSVALD E. RASMUSSEN. 

